A new and useful method and system for estimating LFG generation and gas permeability in a landfill or other subsurface-gas producing body of material is provided. The adjusting portion can pivotally swing to the operation zone and has a partition. A radio board connector mates with any one of multiple connectors on the wireless network access device. The straddle assembly, in cooperation with the inlet and main outlet legs, effects a downhole flow path which directs fluids from the inlet leg through body of the template and out the main outlet leg, bypassing the offset outlet leg. The rotary valve comprises a valve rotor which is rotatable to selectively permit or block flow to the LP turbine from either the first exhaust gas passage or the bypass gas passage.